SLVSDK7C April 2017 – February 2020
PRODUCTION DATA.
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Parameter Measurement Information
- 8 Detailed Description
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
8.3.2 Controlled Turn-On
The TPS22971 has controlled Turn-On for inrush current control. A capacitor to GND on the CT pin adjusts the slew rate. For a given input voltage and desired slew rate, Equation 1 can be used to find the required CT value. For calculated CT values less than 220 pF, use 0 pF instead when solving for tON and tPG,ON.
Equation 1. 
where
- CT is the capacitor on the CT pin (in pF)
- VIN is the input voltage (in V)
- SR is the desired slew rate (in V/µs)
The CT value determined in Equation 1 can be used to find the total Turn-On time, tON, in Equation 2 or Equation 3 depending on VIN.
Equation 2. 
Equation 3. 
where
- tON is the Turn-On time (in µs)
- CT is the capacitor on the CT pin (in pF)
- VIN is the input voltage (in V)